Hall Effect Studies of LPCVD grown β-Ga2O3 on Sapphire

With its ultra-wide bandgap of 4.5-4.9 eV and large breakdown electronic field, β-Ga2O3 has recently attracted attention because of its potential for next generation power electronics applications. The estimated breakdown field for β-Ga2O3 is 8 MV/cm, much larger than 2.5 MV/cm for 4H-SiC and 3.3 MV/cm for GaN, which could enable power electronics with larger power density and greater efficiency [1]. Also, Ga2O3 has the potential to be more cost-efficient in mass production than other wide bandgap materials due to its ability to be synthesized through standard melt growth methods [2]. With this motivation, this study examines the electronic properties of β-Ga2O3 via temperature dependent Hall effect measurements. The Ga2O3 was grown on c-face sapphire substrates via low pressure chemical vapor deposition (LPCVD) using liquid metal gallium and oxygen precursors, with silicon dopants introduced via SiC4 gas. [3] Hall effect measurements were performed to determine carrier density and mobility as a function of temperature. The sign of the Hall voltage indicates that the Ga2O3 is an n-type material with electrons as majority carriers. The temperature dependence of the carrier density indicates activation energies of 10.7 meV and 10.1 meV for the Si dopant using samples with room temperature electron densities of 2×10 18 cm-3 and 3×10 18 cm-3 , respectively. Among several samples, the highest measured mobility was 34 cm2/Vs at room temperature and 40 cm2/Vs at 150K. These results indicate the potential of LPCVD grown Si-doped Ga2O3 for next generation semiconductor power electronics applications. [1] Applied Physics Letters 100, 013504 (2012) [2] Applied Physics Letters 103, 123511 (2013) [3] Applied Physics Letters 109, 132103 (2016